Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds context about what data is returned (fields, geometry, record count, capabilities), but does not disclose potential error behavior, URL validation, or rate limits. This is a moderate value-add beyond the annotations, consistent with a 3.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, well-structured sentence that front-loads the action and resource, then efficiently lists the return types. Every word earns its place; there is no fluff or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With one parameter, strong annotations, and no output schema, the description carries the burden of explaining what the agent will get. It does so by enumerating fields, geometry type, record count, and capabilities, which is sufficient for deciding to call the tool. However, it omits details like response structure or error handling, so it is not fully exhaustive—just short of a 5.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already fully documents the single 'url' parameter with a description and an example, giving 100% coverage. The tool description repeats the idea of 'by url' but adds no new meaning about the parameter format, constraints, or behavior. With high schema coverage, the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Get') and identifies a precise resource ('an ArcGIS Feature/Map Service layer's schema by url'), then lists the concrete data returned: fields, geometry type, record count, and capabilities. This clearly distinguishes it from sibling tools like query_layer, which would query data rather than metadata.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context: this tool is for retrieving schema/metadata from a layer URL. It does not explicitly name alternatives or exclusions (e.g., 'use query_layer to fetch features'), but the purpose is specific enough that an agent can infer when to use it. Since no when-not guidance is given, it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.